<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Document</title>
        <script type="text/javascript">
            /**
             * = 
             *      可以将符号右侧的值赋值给符号左侧的变量
             * +=
             *      a += 5 等价于 a = a + 5
             * 
             * -=
             *      a -= 5 等价于 a = a - 5
             *      
             * *= 
             *      a *= 5 等价于 a = a * 5
             * 
             * /= 
             *      a /= 5 等价于 a = a / 5
             * 
             * %=
             *      a %= 5 等价于 a = a % 5
             *
             */
            
            var a = 123;

            a = a + 5;
            a += 5;

            a -= 5;

            a *= 5;

            a /= 5;

            a %= 5;


            console.log(a);

             

        </script>
    </head>
    <body>

    </body>
</html>